1. Field of the Invention
The present invention relates generally to wireless mesh networks. More particularly, the present invention relates to dynamic channel switching in a wireless mesh network that conforms to an IEEE 802.11s standard.
2. Background Information
Wireless mesh network is a communication network that made of radio nodes organized in a mesh topology. A typical wireless mesh network which aims to provide ubiquitous high bandwidth access for a large number of users often consists of mesh clients, mesh routers and gateways. The integration of the wireless mesh network with other networks such as the Internet, cellular, IEEE 802.11, IEEE 802.15, IEEE 802.16, sensor networks and many more can be accomplished through the gateways and bridging functions in the mesh routers.
In recent years, the wireless mesh network together with related application and services have been actively researched. The wireless mesh network is envisioned as an economically viable paradigm and promising technology for supporting high speed multimedia services. A wireless mesh network that conforms to the IEEE 802.11s is a network that supports direct communication between a plurality of wireless devices having a relay function without utilizing an access point. In the wireless mesh network which is interference-limited, the channel bandwidth is insufficient due to limited spectrum that is shared with numerous mesh links within the network. Co-channel interference, in addition, that is caused by excessive power usage and bad frequency planning is detrimental to the network system capacity and quality of service. Hence, a wireless mesh network that efficiently utilizes network resources and reduces the co-channel interference is crucial.
It is found that one effective way to manage the network resources as well as mitigating the co-channel interference is to employ dynamic channel switching. The dynamic channel switching enables the wireless mesh network to avoid severe interferences in certain parts of the coverage area by shifting to other idle or vacant or less severe channels. The dynamic channel switching virtualizes a wireless mesh network by operating in different frequency channels at different periods of time but not disrupting the network connections. Also, the dynamic channel switching allows the mesh nodes to interact toward each other regardless of their frequency.
The typical prior art approach includes channel scanning and signaling mechanism for the wireless mesh network based on modification on default channel switching announcement frame. Conventionally, the dynamic channel switching is initiated by a default protocol which considers only the interference that is detected, e.g. radar event and the like, on the channel. The default protocol also fails to propose an interference limit beyond which the interference is detrimental to the network connection that requires channel switching. However, the channel switching based on the interference only, at sometimes, is unnecessary and provides no improvements to the quality of service. EP Publication No. 1 936 878, for example, describes a distributed method for channel assignment based on physical and logical factors. The prior art fails to anticipate the dynamic channel switching for the wireless mesh network that utilizes or quantifies factors other than the abovementioned factors that might essential for the switching.
A need therefore exists for providing a method of channel switching for the wireless mesh network that allows for autonomous decision making by quantifying various relevant factors. Thus, the present invention seeks to provide a method of dynamic channel switching for use in the wireless mesh network.